Dodge Dakota 2001, Service Manual

Page: 434 / 2307

minates a rectangular box around the character that
represents the currently selected lever position.
During daylight hours (exterior lamps Off) the gear
selector indicator VFD is illuminated at full bright-
ness for clear visibility. At night (exterior lamps are
On) the VFD lighting level is adjusted with the other
cluster illumination lamps using the panel lamps
dimmer thumbwheel on the headlamp switch. How-
ever, a “Parade” mode position of the panel lamps
dimmer thumbwheel allows the VFD to be illumi-
nated at full brightness while the exterior lamps are
turned On during daylight hours. The gear selector
indicator VFD is serviced as a unit with the instru-
ment cluster.
OPERATION
The electronic gear selector indicator gives an indi-
cation to the vehicle operator of the transmission
gear that has been selected with the automatic trans-
mission gear selector lever. This gauge is controlled
by the instrument cluster circuit board based upon
cluster programming. The cluster circuitry automati-
cally configures itself for the proper automatic trans-
mission
model based upon the hard wired
transmission range sensor mux circuit input to the
cluster. Each time the cluster is disconnected from
battery current for more than about five minutes, it
must configure itself again for the automatic trans-
mission model that is in the vehicle when it is recon-
nected to battery current. The gear selector indicator
information is displayed by a dedicated Vacuum Flu-
orescent Display (VFD) on the instrument cluster
electronic circuit board, and the VFD will not display
the gear selector indicator information after the igni-
tion switch is turned to the Off position. The instru-
ment cluster circuitry configures the gear selector
indicator VFD based upon the following inputs from
the transmission range sensor:
•
Open Circuit - If the transmission range sensor
mux circuit is open, the cluster circuitry controls the
gear selector indicator display based upon electronic
messages received from the electronic Transmission
Control Module (TCM) over the Programmable Com-
munications Interface (PCI) data bus. If the input is
open circuit and no electronic messages are received
from the TCM within two seconds, the instrument
cluster circuitry will cycle the indicated gear selector
position from P, to R, to N, to D to 2 repeatedly and
continuously until the condition is resolved or until
the ignition switch is turned to the Off position,
whichever occurs first.
•
Resolved Circuit - If the transmission range
sensor mux circuit is resolved, the cluster circuitry
controls the gear selector indicator display based
upon the resistance value of the hard wired input
from the transmission range sensor. If the cluster
has configured itself for the transmission range sen-
sor input and detects a short to ground in the trans-
mission range sensor mux input, the cluster will
indicate all positions in the VFD; or, if this input is
open circuit, the cluster will blink all positions in the
VFD. The VFD display for the short-to-ground and
open circuit conditions will continue until the condi-
tion is resolved or until the ignition switch is turned
to the Off position, whichever occurs first.
•
Actuator Test - Each time the cluster is put
through the actuator test, the VFD will display all of
its characters at once, then step through each char-
acter segment individually during the VFD portion of
the test to confirm the functionality of the VFD and
the cluster control circuitry.
On models with a TCM, the TCM continually mon-
itors the transmission range sensor, then sends the
proper gear selector indicator messages to the instru-
ment cluster. On models without a TCM, the instru-
ment cluster continually monitors the hard wired
transmission range sensor multiplexed input. For
further diagnosis of the gear selector indicator or the
instrument cluster circuitry that controls this func-
tion, (Refer to 8 - ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND TESTING). On mod-
els without a TCM, for further diagnosis of the trans-
mission
range sensor, (Refer to 21 -
TRANSMISSION/TRANSAXLE/AUTOMATIC -
42RE/TRANSMISSION RANGE SENSOR - DIAG-
NOSIS AND TESTING) or (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC
- 46RE/
TRANSMISSION RANGE SENSOR - DIAGNOSIS
AND TESTING). On models with a TCM, for proper
diagnosis of the transmission range sensor, the TCM,
the PCI data bus, or the message inputs to the
instrument cluster that control the gear selector indi-
cator, a DRBIII
t
scan tool is required. Refer to the
appropriate diagnostic information.
HIGH BEAM INDICATOR
DESCRIPTION
A high beam indicator is standard equipment on
all instrument clusters. The high beam indicator is
located near the upper edge of the instrument cluster
overlay, between the tachometer and the speedome-
ter. The high beam indicator consists of a stenciled
cutout of the International Control and Display Sym-
bol icon for “High Beam” in the opaque layer of the
instrument cluster overlay. The dark outer layer of
the overlay prevents the indicator from being clearly
visible when it is not illuminated. A blue lens behind
the cutout in the opaque layer of the overlay causes
the icon to appear in blue when it is illuminated
from behind by a replaceable incandescent bulb and
AN
INSTRUMENT CLUSTER 8J - 21
GEAR SELECTOR INDICATOR (Continued)